OBD Codes


Description of the defect

EGR Flow Failure (outside the minimum or maximum limits)
The EEGR system is monitored once per drive cycle during steady state conditions above 48 mph . The test will fail when a malfunction is detected by PCM calculations indicating the EGR flow is less or greater than expected.

Possible causes

List of elements that might trigger the appearance of this code

  • EEGR valve stuck open or closed
  • Connector to EEGR not seated
  • EEGR motor windings shorted or open circuited
  • No power to EEGR
  • Harness open or shorted to power or ground
  • Vacuum signal to MAP restricted or leaking
  • MAF sensor signal erroneous
  • Damaged PCM
  • Carbon build up in EEGR valve seat area
  • One or more sensor not responding or out of range

Diagnostic help

Some tricks to help us for the diagnosis of the failure
All of the following sensors input data to the PCM for proper operation of the EEGR system: ECT, CPS, IAT, MAF, TP, MAP. Any DTC relating to these sensors must be resolved prior to addressing P0400 code.

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